Discover Available Hashing Algorithms in Python with hashlib

When working with hashes in Python, the hashlib module is the go-to library. It provides various hashing algorithms to choose from. You can easily generate cryptographic hashes of data like files or strings using this library, but sometimes it's important to know which algorithms are available for use in your specific environment.

Discovering Available Hashing Algorithms

Python’s hashlib library allows you to check the available hashing algorithms on your current platform. You can do this by using the hashlib.algorithms_available and hashlib.algorithms_guaranteed attributes. These give you insight into which hashing algorithms can be used on your system.

Using hashlib.algorithms_available

The hashlib.algorithms_available attribute provides a set of algorithms that are available in the current Python interpreter, depending on the platform you're using. These algorithms vary by the platform, the Python version, and any available external libraries or cryptographic backends.

Here’s how you can view the available algorithms:

import hashlib
 
# Display the available hashing algorithms
print(hashlib.algorithms_available)

Example Output:

{'sha256', 'DSA-SHA', 'SHA512', 'SHA224', 'dsaWithSHA', 'SHA', 'RIPEMD160', 
 'ecdsa-with-SHA1', 'sha1', 'SHA384', 'md5', 'SHA1', 'MD5', 'MD4', 'SHA256', 
 'sha384', 'md4', 'ripemd160', 'sha224', 'sha512', 'DSA', 'dsaEncryption', 
 'sha', 'whirlpool'}

Explanation:

• This set shows various algorithms, including popular ones like SHA-256, SHA-1, MD5, and others.
• Some algorithms are cryptographic standards like SHA-512 and SHA-1, while others may be platform-specific or less commonly used, like whirlpool or DSA-SHA.

Using hashlib.algorithms_guaranteed

While hashlib.algorithms_available lists all the hashing algorithms available in the current environment, hashlib.algorithms_guaranteed is a subset that provides only those algorithms that are guaranteed to be available across all Python platforms and interpreters.

This ensures that your code is portable and will work on any system without relying on platform-specific or external algorithms.

Here’s how you can check the guaranteed algorithms:

import hashlib
 
# Display the guaranteed hashing algorithms
print(hashlib.algorithms_guaranteed)

Example Output:

{'sha256', 'sha384', 'sha1', 'sha224', 'md5', 'sha512'}

Explanation:

• The algorithms listed in hashlib.algorithms_guaranteed are the most common and are available in any Python installation.
• These include SHA-1, SHA-256, SHA-384, SHA-512, SHA-224, and MD5.

Common Hashing Algorithms

Here’s a quick overview of some common hashing algorithms available in hashlib:

1. SHA-1 (SHA1)

• SHA-1 produces a 160-bit hash value.
• It was widely used but is considered cryptographically broken and deprecated in favor of stronger algorithms like SHA-256.

2. SHA-256 (SHA256)

• SHA-256 produces a 256-bit hash value.
• It is currently one of the most secure and widely used algorithms in cryptographic applications, such as SSL certificates, Bitcoin transactions, and file verification.

3. SHA-512 (SHA512)

• SHA-512 produces a 512-bit hash value.
• It is a stronger, longer version of SHA-256 and provides enhanced security for applications requiring a higher level of protection.

4. MD5

• MD5 produces a 128-bit hash value.
• Although once widely used, MD5 is now considered weak due to vulnerabilities that make it susceptible to collision attacks. It's not recommended for security-critical purposes but can still be used for checksum verification where security is not a concern.

5. RIPEMD160 (RIPEMD160)

• RIPEMD160 is part of the RIPEMD family of cryptographic hash functions.
• It produces a 160-bit hash and offers security features similar to SHA-1, though it is less commonly used.

6. Whirlpool

• Whirlpool produces a 512-bit hash value and is considered a secure hashing algorithm.
• It is used less frequently than SHA-256 but still offers strong cryptographic security.

7. MD4

• MD4 produces a 128-bit hash value.
• Like MD5, MD4 is now deprecated and should not be used for cryptographic purposes due to known vulnerabilities.

Example: Using hashlib to Hash Data

Now that you know the available algorithms, you can use them to hash data in Python. Here’s an example of how to hash a string using SHA-256:

import hashlib
 
# Create a new SHA-256 hash object
hasher = hashlib.new('sha256')
 
# The message to hash
message = "Hello, world!"
 
# Update the hash object with the message (encoded as bytes)
hasher.update(message.encode())
 
# Print the hexadecimal digest of the hash
print("SHA-256 Hash:", hasher.hexdigest())

You can easily switch to another algorithm by changing the name in hashlib.new():

# Using SHA-512
hasher = hashlib.new('sha512')
 
# Using MD5
hasher = hashlib.new('md5')

Conclusion

Understanding which hashing algorithms are available in your Python environment is essential for choosing the right tool for your cryptographic needs. By using hashlib.algorithms_available and hashlib.algorithms_guaranteed, you can easily determine which algorithms are supported on your platform.

In this article, we covered how to list the available algorithms in Python, highlighted some common hashing algorithms, and provided examples of how to use them. Whether you're working with security-critical applications or simple file checksums, hashing is a powerful technique that plays a key role in modern software development.